Derivatives of cyclopentanetetracarboxylic acid



United States Patent 3,455,990 DERIVATIVES 0F CYCLOPENTANETETRA- CARBOXYLIC ACID Barry David Jones, and James Christopher .Phillips Sly,

Tonbridge, Kent, England, assignors to Bridge Chemicals Limited, Hertfordshire, England, a British company No Drawing. Filed Dec. 1, 1965, Ser. No. 510,974 Claims priority, application Great Britain, Dec. 11, 1964, 50,640/ 64 Int. Cl. C07c 133/02 US. Cl. 260-468 6 Claims ABSTRACT OF THE DISCLOSURE Polyhydrazide derivatives of cis-cyclopentanetetracarboxylic acid are prepared by reacting lower alkyl esters of cyclopentanetetracarboxylic acid with appropriate quantities of a source of hydrazine. The compounds prepared have at least two hydrazide groups and are useful as blowing agents and herbicides.

wherein R R R and R represent NHNH or OR, where R represents a hydrocarbon group containing up to 12 carbon atoms, preferably an aliphatic group, for example an alkyl group, the values of R R R and R being such that at least two of them are NH--NH The compounds of Formula I may be prepared by reacting a tetra-ester of CPTCA of the general formula:

ROOCHCCHCOOR ROOC-HC CH-COOR wherein R has the same meaning as in Formula I, with an appropriate amount of hydrazine depending on whether the tetra-, trior di-hydrazide is required. The reaction is preferably carried out in the presence of water and/ or an organic solvent, for example methanol, ethanol or dimethyl formamide. The hydrazine may, if desired, be used in the form of hydrazine hydrate.

In copending US. application Ser. No. 471,414 filed July 12, 1964 by Sly, Hansell and Flavell, there is described the preparation inter alia of some tetra-esters which may be employed in preparing the compounds of the present invention.

3,455,990 Patented July 15, 1969 "ice The compounds of the invention are useful as blowing agents. They may also be of use as herbicides.

The following exaamples illustrate the invention.

Example 1 The tetramethyl ester of all-cis CPTCA (30.2 g.), referred to in Chem. Ber. 87, 1752-9, 1954, was mixed with ethanol (250 ml.) and 40% w./w. aqueous hydrazine (37.5 g.). The resulting mixture was heated under reflux for 5 /2 hours and was then cooled, filtered and the precipitate dried to give the tetra-hydrazide of all-cis CPTCA (20 g.).

Example 2 The tetramethyl ester of all-cis CPTCA (30.2 g.) was mixed with 40% w./w. aqueous hydrazine (35.2 g.) and the mixture was heated under reflux for 2 hours. It was then cooled, filtered and the precipitate dried to give the tetra-hydrazide of all-cis CPTCA (23 g.).

Example 3 The tetramethyl ester of all-cis CPTCA (3.02 g.) was mixed with dimethyl formamide (10 ml.) and hydrazine hydrate (2.2 g.). The mixture was heated at C. for 2 hours. It was then cooled and filtered, and the precipitate was washed with hot ethanol and then dried to give the tetra-hydrazide of all-cis CPTCA (1.7 g.).

Example 4 A solution of the tetramethyl ester of all-cis CPTCA (3.02 g.) in methanol (20 ml.) was added dropwise to refluxing hydrazine hydrate (10 ml.) over 45 minutes. The resulting mixture was heated under reflux for a further hour and was then cooled, filtered and the precipitate washed with hot methanol to give the tetra-hydrazide of all-cit CPTCA (2.61 g.).

Example 5 The tetramethyl ester of all-cis CPTCA (7.55 g.) was mixed with methanol ml.) and hydrazine hydrate (3.75 g.) and heated at reflux for 6 hours. Some of the methanol was removed by distillation and the resulting solution was then cooled and filtered to give the trihydrazide monomethyl ester of all-cis CPTCA (2.5 g.).

Example 6 The tetramethyl ester of all-cis CPTCA (75.5 g.) was mixed with methanol (200 ml.) and hydrazine hydrate (25 g.) and heated at reflux for 4 hours. It was filtered hot and the filtrate cooled to 0 C. The solid formed was filtered ed to give the dihydrazide dimethyl ester of all-cis CPTCA (28.6 g.).

We claim:

1. Hydrazides of all-cis 1,2,3,4-cyc1opentane-tetracarboxylic acid represented by the general formula:

wherein R R R and R represent NHNH or OR, where R represents a hydrocarbon group containing up to 12 carbon atoms, the values of R R R and R being such that at least two of them are NHNH 2. Hydrazides as claimed in claim 1, wherein -R rep- References Cited resents an aliphatk P UNITED STATES PATENTS 3. Hydrazldes as clalmed in claim 1, wherein R represents an group. ,8 957 WOlf 260'-326 A hydrazide as claimed in claim 1, wherein Rb R2, 5 3,346,598 10/1968 Volkenburgh et a1. 260-3463 R and R each represent NH-NHg.

5. A- hydrazide as claimed in claim 1, wherein one of LORRAINE WEINBERGER Pnmary Exammer R R R and R is methoxy and the remainder are each PAUL J. KILLOS, Assistant Examiner U s 01 XR 6. A hydrazide as claimed in claim 1, wherein two of 10 R R R and R are methoxy and the remaining two are 260-557; 71106, 118 NHNH 

